Injector for feeding locomotives or other boilers



H. DEUTSCH June 1'9, 1934.

INJECTOR FOR FEEDING LOCOMOTIVES OR OTHER BOILERS Filed sept. 29, 1952 N ve/V Tw? Patented June 19, 1934 UNITED STATES INJECTOR FOR FEEDING LoooMoTIvEs R OTHER BOILEBS Hans Deutsch, Vienna, Austria,

Alex. Friedmann,

assignor to firm Vienna, Austria Application September 29, 1932, Serial No. 635,442

In Germany July 2 Claims.

This invention relates rto injectors for feeding locomotives or other boilers, particularly of the type intended to work against high boiler pressures. Various economical reasons have led to 5 the use of high pressures in locomotive boilers and this had the consequence that the working of the injector will become very unstable when the temperature of the feed water exceeds a certain limit.

Now, especially with locomotives the water of the tender is exposed to the sun and to other inuences which tend to raise its temperature. In tank-locomotivesthe heat from the boiler will to a certain extent cause a raising of the temperature of the feed water. Thus a comparatively high feed water temperature is a feature which has to be considered as necessary.

Therefore, the introduction of boilers with high pressure has had the consequence that injectors were eliminated and that the boilers were fed with pumps having a piston, in spite of the fact that pumps have marked drawbacks when compared with injectors. 'I'hey are much more expensive, their'working expenses are high, their weight is much higher than the weight of the injector and they must be treated with more care. Re-introduction of a reliable injector service in these cases is therefore a marked advantage.

Now, the special causes of the unreliability of the injector, when working against high boiler pressures and when fed with water of comparatively high temperature have been investigated and it has been found that said unreliability of the injector is caused by a loss of feed water at the overflow valve when the feed water temperature exceeds a certain and given limit. It has, moreover, been found that the quantity of water that is thusr lost through the overflow valve, in-

creases when the temperature of the water will increase so as to exceed said limit.

This limit according to said investigations is itself dependent upon the boiler pressure against which the injector must work and it is lower when the boiler pressure is high and vice versa. Thus the boiler pressure has a direct influence upon the temperature of the feed water with which the injector is still capable of work.

The sensitivity of the injector with respect to the increase of the temperature of the feed water is probably a consequence of the fact that the mixing temperature within the injector will increase with an increase of the temperature of the feed water and with increasing boiler pressure. Now, when the mixing temperature within the injector increases, also the pressure within the 2, 19sty overflow chamber will increase and when by virtue of such increase the overflow pressure reaches the atmospheric pressure, the overow valve is opened'so that losses of feed Water occur.

To avoid such losses it would be an obvious proposal to load the overflow valve after the beglnning of the feeding automatically o1l by some hand control means in order to allow an excess of pressure above the atmospheric within the overflow chamber and thus the feeding of water I of a higher temperature without losses in the overflow chamber. Such a means, however, cannot be employed or if employed will only be of very little advantage because the increase of pressure in the overflow chamber is not admissible over a certain extent; the water would in such a case be retained and not have an opportunity to enter into the nozzles of the injector. Thereforeother means must be proposed to overcome the above mentioned diiculties.

My invention relates to these means and it has been found that allI the various dimculties that have been mentioned and which prevent the use high pressure boilers can be eliminated by a certain design of the injector accordingy Ito which the relative dimensions of certain parts of the injector are chosen according to a given principle.

, In order to give a simple rule for this new design which I employ I will term the steam nozzle of the injector which carries the largest quantity of steam to the nozzle system the main steam nozzle and the quantity of steam passing therethrough the main steam quantity. The remaining quantity of steam introduced into the nozzle system shall be termed auxiliary steam quantity. The auxiliary steam has, as is well known, the function of leading the feed water into the nozzle system in the same way as an ejector would do. The entire cross section through which the water will be introduced into the nozzle system either by one or by a plurality of openings shall be termed the water admission cross section.

According to my invention I employ two means which are interdependent and which are both intended to secure a relatively low mixing temperature within the injector which in its turn will have the consequence that a low pressure will prevail in the overflow chamber. The first of these means consists in choosing the ratio of the water admission cross section to the nozzle system relatively to the cross sections through which the auxiliary steam quantity enters into the injector in such a manner that it will be equal to or larger than 4. It has 'been found that with a ratio of said cross sections that is larger "than the value 4 a suiciently low temperature is always prevailing near the mouth of the main steam nozzle.

The second means to be applied, which can only be employed when the correct value of the Iratio of the cross sections above explained has been chosen and thus permits its application, consists in trying to utilize as far as possible the kinetic energy of the main steam quantity and for this purpose the ratio between the cross section of the mouth of the main steam nozzle and thesmallest cross section through which the main steam quantity passes will be chosen in such a manner that its value is eoual to or larger than 3. This value of said ratio means that the ex pansion of the steam is carried as far as possible and thus a relatively small quantity of steam will be' necessary to overcome the high boiler pressure.

, The selection of this value also will cause a decrease of the mixing temperature within the injector and thus will also contribute to maintain a small pressure within the overflow chamber. In spite of this fact the velocities of the fluids within an injector according to this invention are such that very high boiler pressures can be overcome.

The invention is illustrated in the accompanying drawing in which two modications of injectors constructed according 'to the above explained principles are shown. Fig. l is a longitudinal vertical section of a preferred form of my injector. Fig. 2 is a smaller sectional view of a modification of the improved injector. Similar parts are designated by similar referenceI nume bers in both'gures.

In Fig. l an injector is illustrated which comprises a casing l and a main steam nozzle 2. The area of the cross section F of the mouth of the main steam nozzle is at least three times the area of the smallest cross section f of the nozzle. The area of the 'cross section through which the water enters into the nozzle system and which is designated by the reference W in the drawing is at least four times the area of the annular cross section d through which the auxiliary steam Quantity will enter into the nozzle system.

By virtue of this construction the quantity of water entering through the annular cross section W is very large so that it will condense the quantity of steam entering through the main steam nozzle 2 within the combining or mixing nozzle 4 very rapidly. The Various particles of the main steam. quantity which are leaving the cross section F have a very great velocityand are thus accelerating the water particles in the smallest cross section of the nozzle system in such a manner that a high pressure will prevail in thepressure chamber 6.

In the modification shown in Fig. 2 the main steam nozzle 2 projects farther into the nozzle system than the Various auxiliary steam nozzles which are represented by the steam nozzle 3 in the drawing. By means of this nozzle a rlarge quantity of water will be fed through an annular cross section which surrounds the main steam nozzle to the mixing nozzle 4. When the dimensions are chosen in the way above indicated acceleration of the water particles in the smallest cross section 5 will occur so that the feeding pressure within the pressure chamber 6 will be much higher than the feeding pressure that can be obtained with injectorsl hitherto known.

The above explained principle of my invention may of course be realized also in Various other ways.

What I claim is:-

l. An injector capable of feeding against high boiler pressures, comprising a main steam nozzle, auxiliary steam nozzles and a water admission cross section located between the mouth of the main steam nozzle and the adjacent auxiliary steam nozzle, being next in the direction of the steam jet, said main steam nozzle having a degree of expansion corresponding to a ratio of cross sections between the smallest cross section which determines the quantity of main steam to be discharged and the cross section at its mouth which is equal to or larger than three.

2. An injector capable of feeding against high boiler pressures, comprising a main steam nozzle, auxiliary steam nozzles and a water admission cross section, located between theniouth of the main steam nozzle and the adjacent auxiliary steam nozzle, being next in the direction of the steam jet, said main steam nozzle having a degree of expansion corresponding to a ratio of cross sections between the smallest cross section determining the quantity of steam and the cross section at its mouth equal to or larger than three and said water admission cross section being at least four times as large as the cross section through which lthe auxiliary4 steam enters into -the injector.

HANS DEUTSCH. 

